Veneer structure.



K. MUTTER.

' VENEER STRUCTURE.

APPLICATION FILED OCT. 24, 1912.

1,058,701 Patented Apr. 8, 1913 wi hisseg l 1710421162 gQ/Q, 401 War! all KARL MUTTEE, 0F GaRwIHL, GERMANY.

VENEER STRUCTURE.

Specification of Letters Patent.

Patented Apr. 8, 1913.

Application filed October 24, 1912. Serial No. 727,475.

To all whom, it may concern:

Be it known that I, KARL-MU'ITER, a citizen of the German Empire, and residing at Gorwihl, Baden, Germany, have invented certain new and useful Im rovements in Veneer Structures, of which t e following is.

the desired objects, or by'employing suitable,

formers the layers of veneer can heso arranged one above'a'nother that rods, tubes, vases or objects of other forms, are directly obtainable. It has moreover already been proposed to employ for these known processes veneers obtalned by removing on a lathe spiral layers from the trunk of a tree. The veneers thus obtained have greater strength than those obtained in the usual manner 71. e. by dividing the trunk segmental1y (as b in Figures 1 and 2) because when removing spiral layers from trees of regular growth the various cohesive annual rings are less frequently cut through.

If there be removed from the trunk of a tree, 6. g. a coniferous tree, a. strip forming ortion of a single annual ring (see a in igs. 1 and 3), and if this strip be examined, 1

it is readily seen that the wood in one and the same annual ring is not homogeneous throughout. Each annual ring is found to consist of two layers, the one being throughout its structure not only comparatively soft and porous and therefore of little strength. but also highly hygroscopic, while the other, though occupying less space is remarkably dense, of great strength, and, owing to the high percentage of rosin present, is practically non-hygroscopic. The first-named layer of the annual ring 'forms during the spring and will hereinafter be called springwood, the latter layer forms in summer and will he therefore called summer-wood.

According to my invention the veneer is first removed from the trunk in layers exactly parallel with the annual ring (see a Figs. 1 and 3) andpreferably in the form of cheap kinds of Wood can be strips (6, Fig. 4) thereu on the soft springwocd (as indicated in the drawing by the dotted portions of the sections) is peeled off from the hard summer-wood (as indicated by the full lines in said sections) leaving a veneer as a in Fig. 3. It is from such a veneer that I make the said rods, tubes, blocks and the like.

I have found that objects manufactured from veneers consisting only of the thin, hard summer-wood, even when such objects are of considerably less weight and occupy considerably less space, have remarkably greater strength and rigidity than objects manufactured by the said known processes. My invention further makes possible the employment of those woods. of a porous na ture which have hitherto been inapplicable to the more useful purposes, and hence many utilized for making objects having the advantages just described. Moreover hitherto in a great number of varieties of wood the only portion Within the trunk which. could be employed for a large number of purposes was the socalled heart-wood, which, because more central, was older and capable of offering greater resistance. According to my invention however the new, external Wood, that portion consisting of the less resisting annual rings, 2'. e. the so-called sap-wood, can be utilized by, removing therefrom all but the summer-wood. I

In known processes of manufacturing rods and the like from the ordinary veneers, the pores-ofthe layers of spring-wood, so thoroughly absorb the glue that considerable increase of weight results without a corresponding increase either of strength or, since the glue is hygroscopic, of imperviousness to moisture. As objects so manufacturedwill naturally alternately get dry and then again absorb moisture, they will not only become warped but, owing to the decomposition of the sap present in springwood, especially in the cheaper kinds, will eventually become rotten and perish.

The veneer a consisting entirely of summer-wood is naturally saturated with rosin and therefore absorbs practically no glue when the strips of veneer are glued one above another, so that when a strong pres sure is applied to the superposed layers of veneer almost all the glue is squeezed from the intervening spaces and only a thin interposing layer of glue remains. The objects manufactured according to my invention are therefore quite unaffected by variable hygroscopic conditions, do not warp and have practically unlimited durability.

' Figs. 5 and 6 show the manner in which tubes are manufactured by superposing, and gluing together layers of my novel veneer. In the example illustrated the wall of the tube is formed of four layers of this veneer, a portion of the layers being, in Fig. 6 shown cut away for the sake of clearness. The inmost layer is wound like a single screwthread, the next two layers being wound like multiple screw-threads, the one a left and the other a right hand thread; the outer layer consists of strips of veneer running longitudinally.

Owing to their great strength, light weight and non-hygroscopic qualities, the rods, tubes and the like made according to my invention are specially suitable for such purposes as building up the ribs of aeroplanes, the cars of air-ships and the like.

I claim 1. Veneer structures, consisting of layers of veneer composed entirely of summerwood, said layers being arranged one above another, and glued one to another under pressure.

2. Veneer structures, consisting of layers of veneer formed of longitudinally disposed strips composed entirely of summer-wood, said layers being arranged one above an other with the strips in adj acent layers cross-- ing one another, and being finally glued one to another under pressure.

3. Tubesconsisting of a plurality of annular layers of veneer composed entirely of summer-wood, said layers being arranged one above another, each layer consisting of strips wound spirally, the strips in adjacent layers crossing one another and being glued together imder pressure.

In testimony whereof, I afiix my signature in the presence of two witnesses.

KARL MUTTER.

Witnesses GEO. Glrroan, ARNOLD ZUBER. 

